Anti-Tip Chair Foot

ABSTRACT

Disclosed is an anti-tip chair leg device that is attachable to the foot of a chair&#39;s rear leg, to prevent or reduce the risk of the chair tipping over backwards. This feature of the device is especially beneficial when a child is using the chair. The anti-tip chair leg device has a leg receiver housing mounted on a footplate. The leg receiver housing has means to grip the lower (or foot) portion of a leg of the chair leg received into the leg receiver housing. The grip means holds the foot of the chair leg in place when the chair leg is received in the leg receiver housing. The footplate then acts to shift the distance of a tipping moment-arm of the chair backward and away from the center of mass of the chair and increase the force required to tip the chair backward.

CONTINUITY DATA

The present application is a divisional of and claims the benefit ofprior filed U.S. non-provisional application Ser. No. 14/595,821, filed13 Jan. 2015 (pending); which in turn is a continuation-in-part of andclaims the benefit of prior filed U.S. non-provisional application Ser.No. 13/953,745, filed 30 Jul. 2013 (now abandoned), U.S. provisionalapplication Ser. 62/044,851, filed 2 Sep. 2014, and prior filed U.S.provisional application Ser. 62/025,516, filed 17 Jul. 2014; the contentof all said prior applications being herein incorporated-by-reference.

FIELD OF THE INVENTION

The present invention is in the field of devices for supporting theweight of a person in a seated position (Class 297). Specifically, thepresent invention relates to chairs having means to prevent the chairfrom falling over backwards (subclass 310). More specifically, thepresent invention is a leg attachment for aiding in the structuralstability of the chair (subclass 463.1).

SUMMARY OF THE INVENTION

The present invention is an attachable anti-tip chair leg device. Thechair leg device is “anti-tip” or “anti-tipping” in that it isattachable to the foot of a chair leg and improves the stability of thechair. That is, the anti-tip leg device prevents or reduces the risk ofthe chair from falling over by increasing the amount of force requiredtip the chair backward. This feature of the present invention isespecially beneficial when a child is using the chair. As shown in thefigures, the anti-tip leg device comprises: a footplate, a leg receiverhousing, and a grip means that holds the chair leg in place. Theanti-tip leg chair device is intended to attach to the lower (or foot)portion of a chair leg on the two back legs of a chair.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an embodiment of the present attachableanti-tip chair leg device showing the opening of the leg receiverhousing.

FIG. 1B is a perspective view of the leg receiver housing of the presentattachable anti-tip chair leg device showing a relationship of thewedges of the gripping mechanism prior to being inserted into theopening of the leg receiver housing.

FIG. 2A is a side elevation cross sectional view of the presentattachable anti-tip chair leg device showing the relationship of thefront and rear wedges of gripping means to the key ridges of the legreceiver housing, and an alternative embodiment of a rear wedge grip.

FIG. 2B is a side elevation cross sectional view of the leg receiverhousing portion of the present attachable anti-tip chair leg deviceshowing the relationship of the leg gripping means to a chair leg (inphantom) retained in the leg receiver housing.

FIG. 3 is a front elevation cross sectional view of the presentattachable anti-tip chair leg device showing a reinforcing bead or weld.

FIG. 4 is a rear elevation cross sectional view of the presentattachable anti-tip chair leg device showing the leg receiverhousing/socket mounted in a recess in the top-side of the footplate.

FIGS. 5A & 5B are top plan views of the present attachable anti-tipchair leg device showing alternative embodiments of the opening of theleg receiver housing, and an alternative footplate configuration.

FIGS. 6A & 6B are side elevation cross sectional views of the legreceiver housing portion of one embodiment of the present attachableanti-tip chair leg device illustrating an alternative means foradjusting the receiver housing to grip chair legs of different sizesand/or configurations.

FIG. 7A is top plan and side elevation views illustrating an alternativeembodiment of the present anti-tip chair foot practiced from a singlesheet metal work piece.

FIG. 7B is side elevation, top plan and rear-end elevation viewsillustrating the work piece of FIG. 7A after being initially folded asindicated.

FIG. 7C is top plan and rear-end elevation views illustrating the workpiece of FIG. 7B after being finally folded as indicated.

FIGS. 7D & 7E respectfully are top plan and partial side elevationcross-sectional views of the finished work piece of FIG. 7C illustratinga chair lag retained in the leg receiver housing of the presentinvention.

FIG. 7F is a top plan view of the finished work piece of FIG. 7Cillustrating an alternative means for retaining a chair leg in the legreceiver housing of the present anti-tip chair foot.

FIG. 8A is top plan and side elevation views illustrating anotheralternative embodiment of the present anti-tip chair foot practiced froma single sheet metal work piece.

FIG. 8B is side elevation, top plan and rear-end elevation viewsillustrating the work piece of FIG. 8A after being initially folded asindicated.

FIG. 8C is side elevation, top plan and front-end elevation viewsillustrating the work piece of FIG. 8B after being folded as indicated.

FIG. 8D is top plan, front-end and side elevation views of the finishedwork piece of FIG. 8C.

FIGS. 9A and 9B is a perspective view illustrating an alternativeembodiment of the present anti-tip chair foot practiced with thefootplate and the leg receiver housing integrated as a single moldedpiece.

FIG. 9C is a top plan view of the embodiment of FIGS. 9A & 9Billustrating use of leg grips and an adjustable leg engaging means.

FIGS. 10A to 10C respectively are back-end, front-end and sideelevations views of the molded embodiment of FIGS. 9A-9C, adapted toutilize a “string-tie” or “zip-tie” as a chair leg engaging means.

FIGS. 11A and 11B are side elevation views of the present anti-tip chairfoot showing an adjustable leg engaging means and the leg receiverhousing from the rear (A) and from the front (B) of the devicerespectively.

FIG. 12A is a combination top plan and side elevation of an alternativeembodiment of the present invention wherein the leg receiver ispivotally connected to the footplate via a bendable/flexible joint.

FIGS. 12B and 12C respectively are side elevation and top plan views ofthe device of FIG. 12A with the foot of a chair leg fixed in the legreceiver.

FIG. 12D is a side elevation view similar to FIG. 12B, but illustratingan alternative means of clamping/fixing the front of the leg receiverhousing to the chair leg.

FIGS. 2. 13A & 13B are each a combination of top plan and side elevationviews of an alternative configuration of a bendable/flexible joint forpivotally connecting the leg receiver housing to the footplate.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, the details of preferred embodiments ofthe present invention are graphically and schematically illustrated.Like elements in the drawings are represented by like numbers, and anysimilar elements are represented by like numbers with a different lowercase letter suffix.

The present invention is an attachable anti-tip chair leg device 10. Thechair leg device 10 is “anti-tip” or “anti-tipping” in that it isattachable to the foot of a chair leg 60 and improves the stability ofthe chair. That is, the anti-tip chair leg device 10 prevents or reducesthe risk of the chair from falling over backwards. This feature of thepresent invention is especially beneficial when a child is using thechair. As shown in the figures, the present anti-tip chair leg device 10comprises three primary components: a footplate 12, a leg receiverhousing 14 and leg grips 18. The anti-tip chair leg device 10 isintended to attach to the lower (or foot) portion 62 of a chair leg 60(see FIG. 2B) on the two back legs of a chair.

In practicing the present anti-tip chair leg 10, the footplate 12 andthe leg receiver housing 14 can be accomplished as initially separatecomponent parts and subsequently joined together, as exemplified inFIGS. 1A to 6B. Alternatively, the footplate 12 and leg receiver housing14 can be accomplished in an integrated fashion from a single (e.g.,sheet metal) starting piece, as in FIG. 7A to 8D, or as a single moldedpiece, as in FIGS. 9A to 11B. In view of the teachings and illustrationscontained herein, an ordinary skilled artisan in this field is able toother manners of accomplishing the footplate 12 and leg receiver housing14 of the present invention.

In the embodiment exemplified in FIGS. 1A & 1B and 2A & 2B, thefootplate 12 has a front-portion 20 and a back-portion 22, a top-surface24 and a bottom surface 26. The footplate 12 is adapted to shift thedistance of the moment-arm backward from the center of mass of the chairto reduce the tendency of the chair to rotate backward about animaginary axis between the points of contact of the back legs of thechair and the floor on which the chair stands. The dimensions of thefootplate 12 in part depend on the configuration of the rear chair leg(i.e., the center of mass of the chair relative to the point of contactof the leg with the floor). It was found that a footplate having anoverall length L of about 4 to 8 inches and a width W of about 2 to 4inches at its widest portion was generally satisfactory for a variety ofrear leg configurations and chair types, with the rear chair leg 60 setback about an inch from the front-edge of the plate 12. Thickness T ofthe footplate 12 depends on the material composition of the plateitself. In a preferred embodiment the footplate was composed of a rigidplastic material with a thickness T of ¼-inch. Depending on the styleand weight of the particular chair the device 10 it to be used on, thefootplate 12 may need to be thicker. A wooden footplate may need to bethicker, and a metal one might be thinner, as is selectable by one ofordinary skill in the art.

The leg receiver housing 14 in a preferred embodiment was an oblong orsquare box, as generally shown in the figures. However, the leg receiverhousing 14 can have other configurations (see FIGS. 5A & 5B), so long asthe interior portions of the front-side 42 and rear-side 44 of the legreceiver housing includes wedge key 16 features to engage the leg grips18. A particular configuration for the leg receiver housing 14 isselectable by one of skill in the art depending in part on theconfiguration or variety of configuration chair leg 60 that the legreceiver housing 14 is to receive. In the embodiments illustrated inFIGS. 3 & 4, the leg receiver housing 14 was a 3-inch square boxconstructed of a ¼-inch thick rigid plastic material with about a2.5-inch receiver housing opening 40, and had an overall height H ofabout 4 inches.

The leg receiver housing 14, into which a rear leg of a chair isreceivable, has an upper-end 54 including an opening 40 into which afoot end 62 of the rear leg 60 of a chair is insertable, and a lower-end56 mounted to the upper surface 24 of the footplate 12. Additionally,the leg receiver housing 14 has a front-side 42 and a rear-side 44. InFIGS. 1A-4, the front-side 42 is shorter than the other three sides ofthe leg receiver housing 14, and is only about ⅔ of the overall height Hof the leg receiver housing 14. This created a gap in the front-side 42,which was continuous with the receiver housing opening 40. The purposeof the gap is to facilitate inserting and seating the chair leg foot 62in the leg receiver housing 14. The front-side gap may be reduced oreliminated for a straight up & down chair leg or for a leg receiverhousing 14 having less overall height H. Embodiments eliminating thefront-side gap are illustrated in FIGS. 8A-10B.

In some of the embodiments illustrated, a wedge key 16 is disposed onthe interior surface of both the front-side 42 and the rear-side 44 ofthe leg receiver housing 14 as shown in FIGS. 2A & 2B. The wedge key 16is a ridge or lip that engages a key way 46 on a leg grip 18 (explainedbelow). The rear-side wedge key 16 b is disposed proximate the upper-endopening 40 (see FIG. 3), and the front-side wedge key 16 a is disposednear the footplate 12 at the lower-end of the leg receiver housing 14(see FIG. 4). The front-side wedge key 16 a positively retains andprevents from slipping the leg grip 18 that engages the lower portion ofthe foot 62 of the chair leg 60, while the back-side grip key 16 bpositively retains and prevents from slipping the leg grip 18 thatengages the foot 62 of the chair leg 60 at an upper portion of the foot62 (see FIG. 2B).

The leg wedge grips 18 have a key-way 46 and a chair leg mating surface48. The key-ways interface with the grip keys 16 of the leg receiverhousing 14 to help hold the wedge grips 18 in place when inserting achair foot 62 into the leg receiver housing, and to prevent the wedgegrips 18 from sliding up or down once the chair foot 62 is in place inthe device 10. The mating surface 48 is adaptable by the skilled artisanto increase the surface area of the wedge grips 18 that interface withthe chair foot 62, as the skilled artisan considers useful. Thecombination of a grip key 16 with a leg grip 18 increases the stabilityof the present device 10 during use by reducing or eliminating thepossibility of the leg grip slipping under a force and resulting in thechair leg 60 pulling out of the leg receiver housing 14.

In the embodiment of FIG. 2B, the leg grips 18 are substantiallyconfigured the same and can be used interchangeably. In an alternativeembodiment, the rear grip 19 was configured as a wedge, which wasinserted and jammed into the leg receiver housing 14 behind the chairfoot 62. In a preferred embodiment shown in FIG. 2A, the wedge grip 19not only has a wedge shape, but also has detents 50 arranged as a seriesof saw teeth. When the wedge grip 19 is inserted into the leg receiverhousing 14 behind the chair foot 62, the detents progressively engagethe grip key 16 of the rear-side of the leg receiver housing 14. Oncefully engaged, the detents limit the movement of the wedge grip 19 toprevent it from slipping out.

Typically, the lower-end of the leg receiver housing 14 of the anti-tipchair leg device 10 is mounted to the top surface 24 of the footplate12, as illustrated in FIG. 3. To improve the strength of the mounting ofthe leg receiver housing 14 to the footplate 12, a reinforcing bead orweld 36 may be drawn along the interface of the leg receiver housing 14and the footplate 12 as shown in FIG. 3. To further reinforce theanti-tip device 10 in the direction of the moment arm, a brace 58 can beadded going from the rear-side 44 of the leg receiver housing 14 to thetop surface 24 of the footplate 12. Additionally and/or alternatively,the footplate 12 can be provided with a recess 34 in the front portion20 of the top surface 24, with the recess 34 disposed for receiving andmounting the lower-end of the leg receiver housing 14 to the footplate12 (see FIG. 4).

As shown in FIGS. 5A & 5B, the opening 40 of the leg receiver housing 14of the attachable anti-tip chair leg device 10 can be adapted to have across section which complements the shape of the chair foot 62 that itis intended to receive. Shown are square and circular openings 40 a & 40b. Also illustrated is that the footplate 12 can be configured indifferent shapes as are selectable by one of skill in the art.

In another preferred embodiment illustrated in FIGS. 6A and 6B, the legreceiver housing 14 has an oblong shape, with the rear-side grip key 16c having an arcuate configuration. Correspondingly, the rear leg grip 18a is adapted to closely receive the arcuate grip key 16 c. In FIG. 6A,the corresponding arcuate configured rear leg grip 18 a is shown firstin a top view, then the rear leg grip 18 a is rotated to a side viewbefore it is shown in place on the rear-side grip key 16 c.

In this embodiment, the front-side leg grip 70 incorporates thefront-side grip keys (ears/tabs) 72, while the leg receiver housing 14and footplate 12 incorporate the mating surface (slot) sets 74 thatreceive the front-side grip keys 72. As illustrated in FIGS. 6A and 6B,the grip keys 72 of the front-side leg grip 70 selectably mate with anyof a series of front-side mating surfaces 74. As exemplified in thefigures, a mating surface set 74 consist a series of a number of alignedreceiver holes and/or slots of two different types: ear slots 76 and keyslots/holes 78. The ear slots 76 receive the ear tabs 72 a of the of thefront-side leg grip 70, and the key slots/key holes 78 receive the keytabs 72 b of the front-side leg grip 70 as it is inserted into a keygrip 72, as illustrated in FIG. 6B.

In one embodiment of the front-side leg grip 70 as exemplified in FIG.6B, the leg grip has a leg shim 82 with a first thickness mounted on onesurface. Optionally, the second surface of the leg grip 70 also can havemounted thereon an alternative leg shim 84 having a different thickness.This allows the leg grip 70 to be inserted into a mating surface set 74with a surface/shim orientation that brings the appropriate thickness ofleg shim 82, 84 to bear against the chair leg 60.

In an alternative embodiment exemplified in FIGS. 7A to 7C, the presentanti-tip chair foot 10 is practiced from a single sheet metal work piece100. The figures illustrate a technique for accomplishing the presentinvention starting from a single piece of sheet metal. FIG. 7Cillustrates a completed work piece integrating the footplate 12 and theleg receiver housing 14. The initial sheet metal work piece 100 shown inFIG. 7A has two slots 94 cut out of it. Additionally, in the embodimentillustrated, the sheet metal work piece 100 initially has a pair of legclamp mounting means 98 (thru holes 98 a) in a position the will becomethe front-side 42 of the leg receiver housing 14 in the finished workpiece. The leg clamp mounting means 98 provide for attaching or mountingan adjustable leg clamp 17 to the leg receiver housing 14. The dashedlines in FIGS. 7A and 7B indicate a line along which the work piece 100is to be bent to accomplish the integrated footplate 12 and leg receiverhousing 14 of this embodiment. FIGS. 7B and 7C also include an elevationview of the work piece as viewed from the rear portion 28 of thefootplate 12.

FIGS. 7D and 7E illustrate this embodiment utilizing a “U-bolt” typefastener as an adjustable leg clamp 17 a to grip and secure the chairleg 60 within the leg receiver housing 14. FIG. 7F illustrates use inthis embodiment of a “zip” or “cable” tie as an adjustable leg clamp 17b to grip the chair leg 60 and secure it within the leg receiver housing14. Other types of adjustable leg grips are intended for practice in thepresent invention, as exemplified in certain of the figure to follow.For example, the subsequent figures illustrate an additional alternativemeans for accomplishing an adjustable leg clamp practicable in thepresent invention to secure the chair leg 60 within the leg receiverhousing 14.

FIGS. 8A to 8D illustrating another alternative embodiment of thepresent anti-tip chair device 10 practiced from a single sheet metalwork piece 100. This embodiment can be practiced in a manner similar tothat of FIGS. 7A to 7F, and differs in that a chair leg 60 is insertedor slid into the leg receiver housing 14 from the front portion 30 ofthe anti-tip chair device 10, rather than from the rear portion 28, asin FIGS. 7A-7F.

FIGS. 9A to 10C illustrate an alternative embodiment of the presentanti-tip chair foot 10 a practiced with the footplate 12 and the legreceiver housing 14 integrated as a single molded piece. The materialcomposition and the dimensions of the footplate 12 are selected toprovide the structural integrity necessary to avoid bending or breakingunder planned loads forces ranges. FIGS. 9A-9C show the leg clampmounting means 98 that provides for attaching or mounting an adjustableleg clamp strap 17 c to the leg receiver 14 a. The adjustable leg clampmeans 17 c is a “zip” strap & closure as illustrated. FIGS. 11A & 11Bshow the adjustable leg clamp means as a “dimpled” strap & closure 17 d.

FIGS. 10A to 10C exemplify alternative means of accomplishing a legclamp mounting means for attaching or mounting a closure means to thesides of a leg receiver 14 a. FIGS. 10A & 10B illustrate use of loop legclamp mounting means 102 fixed to the sides of the leg receiver housing14, through which an adjustable closure strap may be passed. FIG. 10Cillustrates use of a retention channel leg clamp mounting means 104fixed to the sides (and outer surface) of the leg receiver 14 a, alongwhich an adjustable closure strap may be passed. FIG. 10C illustratesuse in this embodiment of a “zip” or “cable” tie as an adjustable legclamp 17 b to grip the chair leg 60 and secure it to the leg receiver 14a. Other leg clamping/gripping means are known to and selectable by oneof skill in this art for practice in the present invention.

FIGS. 11A and 11B illustrate the present anti-tip chair foot device 10 ahaving an embodiment wherein the leg receiver 14 a receives a chair leg60 from the rear portion 28 of the footplate 12 of the anti-tip chairdevice 10 a (FIG. 11A), and an embodiment wherein the leg receiver 14 areceives a chair leg 60 the from the front portion 30 of the footplate12 of the anti-tip chair device 10 a (FIG. 11B). Also shown is analternative embodiment of the adjustable leg clamp 17 means as a“dimpled” strap & closure 17 d.

FIGS. 12A-12D and 13A & 13B illustrate the present anti-tip chair foot10 having embodiments wherein leg receiver housing 14 and the legreceiver 14 a portion of the anti-tip chair foot device 10 are samestructure, which is pivotally connected to the footplate 12. In thisembodiment, the footplate 12 and the leg receiver 14 a are pivotable orbendable about a joint 112. See FIGS. 12A & 12B and FIGS. 13A & 13B. Asillustrated in the figures, the leg receiver 14 a is on one side of thebendable joint 112, and the footplate 12 is on the opposite side. InFIGS. 12A-12D, the bendable joint 112 is accomplished using apin-and-knuckle assembly 112 a. Also illustrated in FIG. 12D is analternative means of clamping/mounting a leg receiver 14-14 a to a chairleg 60 using a screw type fastener 17 e. Because it is beneficial thatthe (angular) relationship between the leg receiver 14 a and thefootplate 12 be fixable (i.e., the footplate 12 does not droopexcessively when the chair is moved), preferably there is a highfriction coefficient between the pin 116 and the knuckles 118 of theassembly 112 a.

Other means of accomplishing the bendable joint 112 are known to andselectable by the skilled artisan for practice in the present invention.For example, FIG. 13A illustrates a bendable joint 112 b of a sheetmetal anti-tip chair foot 10. FIG. 13B illustrates a bendable joint 112c in a molded (e.g., plastic) anti-tip chair foot 10, having a fastenerhole 120 in through the footplate 12 portion, through which a tack,screw, or other fastener can be inserted into the bottom of the chairfoot to prevent the footplate 12 from drooping as the chair is raisedfrom the floor. This arrangement can also be used with thepin-and-knuckle joint 112 a to prevent drooping of the footplate 12.These figures illustrate that the pivotable leg receiver 14 a can have avariety of configurations in addition to the front side 42 feature, suchas the leg receiver 14 a having a “winged” configuration with additionalleg clamping means 98 c to facilitate mounting and securing a chair leg60 in the leg receiver 14 a.

While the above description contains many specifics, these should not beconstrued as limitations on the scope of the invention, but rather asexemplifications of one or another preferred embodiment thereof. Manyother variations are possible, which would be obvious to one skilled inthe art. Accordingly, the scope of the invention should be determined bythe scope of the appended claims and their equivalents, and not just bythe embodiments.

What is claimed is:
 1. An anti-tip chair leg device (10 a) attachable toa foot end (62) of a rear leg (60) of a chair, the chair leg devicecomprising: a footplate (12) having a top-surface (24) and a bottomsurface (26); a receiver housing (14) integrated with the footplate (12)as a single molded piece, the receiver housing (14) having a legreceiver (14 a) against which the foot end (62) of the rear leg (60) isreceivable, the leg receiver (14 a); a leg clamp attaching means (98)integral to the receiver housing (14), and adapted to provide forattaching/mounting an adjustable leg clamp (17) to the receiver housing(14); and the adjustable leg clamp (17) adapted to grip and to securethe chair leg (60) to the leg receiver (14 a), the combination of thefootplate (12), receiver housing (14), leg receiver (14 a) and leg clampmeans (17) providing said device (10 a) to reduce a tendency of thechair to tip backward.
 2. The anti-tip chair leg device (10 a) of claim1, wherein the footplate (12) has dimensions and a material compositionselected to provide a structural integrity necessary to avoid bending orbreaking under an appropriate range of tipping moment forces.
 3. Theanti-tip chair leg device (10 a) of claim 1, wherein the leg clampattaching means (98) is adapted for attaching/mounting a “zip” strap &closure adjustable leg clamp means (17 c) to the leg receiver (14 a). 4.The anti-tip chair leg device (10 a) of claim 1, wherein the leg clampattaching means (98) is adapted for attaching/mounting a “dimpled” straptype adjustable leg clamp means (17 d) to the leg receiver (14 a). 5.The anti-tip chair leg device (10 a) of claim 1, wherein the receiverhousing (14) includes leg clamp attaching means (98) that is adapted forfastening the leg receiver (14 a) to the chair foot (62) using a screwtype fastener (17 e).
 6. The anti-tip chair leg device (10 a) of claim1, wherein the leg clamp attaching means (98) is a loop-type leg clampmounting means (102) fixed to a side of the leg receiver housing (14),through which an adjustable closure strap (17) can be passed.
 7. Theanti-tip chair leg device (10 a) of claim 6, wherein the adjustableclosure strap is embodiment of a “zip”/“cable” type tie (17 b).
 8. Theanti-tip chair leg device (10 a) of claim 1, wherein the leg receiver(14 a) of the receiver housing (14) receives a chair leg (60) from therear portion (28) of the footplate (12).
 9. The anti-tip chair legdevice (10 a) of claim 1, wherein the receiver housing (14) of the legreceiver (14 a) receives a chair leg (60) from the front portion (30) ofthe footplate (12).